Contact InformationBack
| Date of Survey | Successful Sample | Response Rate | Standard Error |
| 28/2/2007 | 1018 | 65.2% | 1.6% |
| 22/2/2006 | 1026 | 68.3% | 1.6% |
| 16/3/2005 | 1041 | 65.2% | 1.5% |
| 10/3/2004 | 1023 | 64.7% | 1.6% |
| 5/3/2003 | 1047 | 71.4% | 1.5% |
| 6/3/2002 | 1041 | 59.9% | 1.5% |
| 7-8/3/2001 | 502 | 67.1% | 2.2% |
| 8/3/2000 | 856 | 56.4% | 1.7% |
| 3/3/1999 | 1190 | 62.1% | 1.4% |
| 18/2/1998 | 804 | 54.7% | 1.8% |
